Steamship-driving mechanism



June 14, 1927. "1632 j A. FLETCHER, JR., ET AL '543' .STEAMSHIPDRIVINGMECHANISM i Filed Dec. 5. 1921 Us sheets-sheet 1 June 14 1927.632 54 A. FLETCHER, JR, ET AL 3 STEAMSHIP DRIVING MECHANISM F led Bed.5, 1921 r a Shaets-Sheer 2 June 14,1927.

A. FLETCHER. JR., ET AL STEAMSHIP DRIVING MECHANISM Fil ed Dec. 1921 sSheets-Sheet 3 W w! M Elm/W1 bot S.

, Patented June 14', 1927. I r i V 7 -10 turbinepropelled steamship; 'lnthis branch} bine on tiu'bines is reduced through the me;

the douhleireduction type to the-"relatively im mwmvmtmama'Applieation'meq Dccc-iu be 5; 1321. seri l No. 519,898. I

'lhekpresent inventionwvrel ates to gearing ffilf-iStefilllSililJb andino re specially to amen; structien gfoi increasing the life oi certaintypcs'o'i toothed gearii g'i J "5 Oiie-ot the important-fields fortoothed! geairin'g is' theutilizati'oi'i I oii' such gears for speed:reduction. One service herespeed recluctien isv accomplished by highlyde.

5 velope l types ofteothed geaning is the stea ng that} such pinion mayreeeiVe"tiVenty=five' times -01 more-as n'iuch' Wear as 'the 'Cor're-fispending gear wheeh Theref0re;=thepiiiioh geai w l-ieel f Itfis thepia'otieeinthiShrtFto provide helical teeth forthis type of gearing} iii-(1e v to properly transmit-the --1oadfend-Fat I the san e time avoidexcessive end-{thrust and Vibration and other difficulties 'w-hieh arelihbleto attend straight teeth! A f'lhe pi actiee; heretofore sin theart has been to 1 min the K train of gears until the pinions-are wernout and t'hn lay up the ship unti1- the gearing CallbQ -diSHlBJIIHGQLand i1eW+ piiiion's'wsub stituted and -also other woni out parts. Thispractice is expensive and it is also-dangerous because often times;pinions --are*-run.:-w1*1en they are liable to bleak doiv11j-at -seai Furthern'iose, after the 'g'ear fteeth have *beeli Worn to the extentthatt11e-f2es ot the teeth 5 no longer are of correctz contou1;-*theweanineieases very rapidly ar d 'the-lifekof su-eh teeth cannot be,fflcG'tllffi-tely pi edietefl and they are liable to break unexpectedly:25: vilcie pairshofwiverylarge/gears connectedidie 'l1 =1e-presentinvention solves the adifii'cul rectlyto .a lpi opellemshafti and pairsofirelatles of thezknown art greatlyextehtiihg 01 tilvelysmall".pinions; connected: 'eithe hreat- PI'OLQngingth efig t e lifeu fui z 1yt0-t111$1131t$ Of-th-t1lfbi11$-ili thewsingle i i-such maii'nerthat much 10I1-g61 Wear, of a reduetiom typeiorlli f the -d'oublehreductioii i a secoiid setaofi gearing which may; comprise another) pair:of ire1atively-;1awe gearsganct a, icoi'iesponding pair. of:nelagtiveiy small p'iniona with @the final and jISIlliLllSb 1 of -.ig;.t1 wei-y high speed of the "w diuin of large expensive g ear-ingsets-ofthe single reduction typeand lD ITIEIIiy-CQQSBS ot s10 W speedrequired by, a screw propellem This type of mechanism is necessarily veiy strong and very heavy abecauseptthe horse power Whichis ce1it1 a1ized=in and} transe- 20v mitted to the propeller shaftx It is common practiceto am ange agphirality of' turbines to drive single pi opellei shaftthrough the inteririediLof suehki'ecluction :geari-ngm In this typeeofconstruction iti is; usual to pro-v replacement- One embodimentmf the--pres'- en-t inver tion comprises =GOI1StI 110i3ii1gthe J teeth i'offthelarge' gears and: a1sotheteeth 1 of the pinions so that anypinion andsha-ft singleset of geayscanbeobtaiiied ithout- I pair "of pi-nion'sconnected directly to the tunthine shafts." Ifiboth typesofmechahismzthe train 1 of gearsis; run a fiery-large 'peneentagegi of:the time in ox edirectionbecause the V steamshipamoves' Lfor'ward nearlya-ll v of {then 7 tinielaiich'goes asternon1y1na=sma1iwpartof: 40

i the time. 1' viewgiof the) substantially: pen;

' tinuouseduty imposed upon-theforward: side;

oftthe geaeteethiitsfollows thattthe-forw vai d r v side: of the gear;teeth aisaavornzzoutgwhen the a backing on ,;ster1i lsidei' ofitheteethsis@substantially unwo'rnm The Lwean..;;on.;the for Ward 1;; side M is.a accentuated v by: sliding and grinding, of .thej c0ntacting ages- Lteeth? I due to? vibi: ation; of; the-ship. while; the nteethxai etransmitting the heavy load; Thiswweanmay also be accentuated "by lackof .e'fiieient :lubri cation; accumulatiom of Ldi f't i and grit; and vby y-lniamy 0ther-1 eauseshvhich 'imay shorten the life 0%: the gearsaaThe, rat owbetween 4a a piiiieu sand itsicor'responding gear: may: Joe

on iai ge gean may be 'removect {from its hearings aii in its bearings:and the teeth on I the-{gears and' pinions will continue tomesh properlyWithQHi? ehanging thea desired dii i ectib i of rotation of the: trairoi: gears and 'propellep shafting. When thew-pinion- -is i eversed-fitheback 3 fades-of the teeth ion the =pini01 become the forwarddrlvingifaces and in viewj-of the lac-i wean: err-such haek faces, thegear not change the'fdesired directionaof rotatioii sosithati (thedirection of v m'oyement being transmitted ith 'ough the vgea'r set iremthe driving shaft" to fi1ia1 driv'en shaft is "the same asit WaSzbfeFethe change-is' madefi v .Thepresent invention also contemplates certainconsti uctions i11 the system of i'e- 'as greataastWenty;fivee-0ramoirento tone.1 01 du-ction gear ngwherebyitiispossibletowe verse the faces of any of the gears of a train of gears,thereby still further increasing the life of the gear set.

After having described the present invention in general terms, it may bestated that the principal object of this invention is the apparatus forprolonging the life of gear sets and the like by means of congruoustooth shapes.

Another object of the present invention is the mechanical design of areduction gear set for turbine Ship propulsion and the transmitting ofpower through gearing wherein the gearing is so constructed that thestern or reversed faces of the gear teeth may be arranged to comprisethe driving faces of the gears by reversing certain elements in thegearing.

A still further and more specific object of the present invention isthat improvement in reduction gearing comprising pairs of gear membersprovided with helical gear teeth and with the angle of inclination ofany portion of a tooth upon one gear having a congruous counterpart in acorresponding tooth on a companion gear.

Other and further objects of the present invention will in part beobvious and will in part be pointed out hereinafter in the specificationfollowing by reference to the accompanying drawings forming a part ofthis application and in which like parts are indicated by likecharacters throughout the several figures thereof.

Realizing that the present invention may be embodied in constructionsother than those herein illustrated, and described it is desired thatthe disclosure herewith shall be considered as illustrative and not inthe limiting sense, and that the scope of the claims shall be as broadas the language thereof when interpreted on the disclosure will admit.

Fig. l is a plane view showing the intermediate and driven gears of adouble reduction gear unit adapted for use with a steamship turbine;

Figure 2 is a diagrammatic plan view showing the pinions andintermediate gears of the device shown in Figure 1;

Figure 3 is a diagrammatic detail illustrating the relation of parts;

Figure 4 is a view similar to Figure 3 showing one gear member reversed;

Figure 5 is a diagrammatic view of an elevation of Figure 3 looking inthe direc tion of the arrow X and showing the stern faces of the gearteeth as shaded;

Figure 6 illustrates certain of the parts in Figure 5 when reversed inposition;

Figure 7 is a detail sectional view showing the construction of thelarge gear shown in F ig. 1.

Referring to the drawings and more specially to Figures 1 and 2 whichmore or less diagrammatically illustrate a double reduction gear unitwhich has been chosen as illustrative of the present invention. in thischosen illustration two turbines are illustrated comprising a highpressure turbine 1 and a low pressure turbine 2 which are mounted insuitable casings and bed plates to be set in accordance with engineeringpractice. Each of these turbines are provided with couplings at whichconnect the turbines with the shafts 5 of the first stage reduction gearpinions (3 and T. The reduction gear pinions 6 mesh with large gears 8mounted on the shaft 9 and the reduction pinions 7 driven by the lowpressure turbine Q mesh with large gears 10 on the shaft 11. The shaft5) carries second stage reduction pinions 12 and the shaft 11 similarlycarries second stage reduction pinions 14. These reduction pinions 12and 14 mesh with the main gears 15 which are securely mounted upon themain shaft 16 that isadapted to be connected to the propeller shaft (notshown) by means of a coupler 17. The construction described, so far asgeneral arrangement and organization is concerned, is common practice.

The present invention comprises more specially the arrangement of theteeth, shafts, bearings and couplings in reversed symmetry. Preferablythe teeth are arranged in such manner that a central plane cutting agear at right angles to its axis will divide the gear in such mannerthat when either side is reversed and placed in position of theadjoining side, the angle and shape of the teeth on the replaced sidewill be exactly the same as the angle and shape of the teeth of theoriginal side of the gear. Preferably this arrangement is carried outthrough the entire set of gears so that the shape and size of the gearteeth on the gearing lying on one side of the central plane cutting theaxes of the set or unit will be congruous to the shape and size of thegear teeth on the other side of the plane. This may be carried out byproviding the gears with teeth arranged as shown in Figure 1 whereineach main gear 15 is divided on its tooth face to comprise teeth 18inclined clockwise on one spiral. and teeth 19 inclinedcounter-cloclm'ise on the opposite spiral. The. same arrangen'lent iscarried out as to the pinions l2 and I4- and also as to the large gears8 and 9.

Reference will now be made to Figures 3 and 4; wherein the gear teethare shown diagramn'latically and the teeth on one half of the gear setare shown in full lines while the teeth on the other half of the gearset are shown in dotted lines, in order to distinguish the teeth so thatthey may be followed by explanation when the reversal has been made. Theset of teeth A are shown in full lines and the set of teeth B are shown11; aoai lines; In "ri -urea "the ama 9 has been reversed, that is;itzhas beenz turnedq end for, end, so: that the pinion 13 is now inengagei'nent with :the teeth; of the large gear AF-andthe; pinion A}?isin engagement w th: the teeth of the large gear-r Theefl'ectioffl-this reversaliofIt'henshaft 9 is shownialso, in: Figures 5 audit. rilnhhgure 5, wln'chgis a diagrammaticend view"offlf 'gure 3, the;

stern faces on the several gears are shown in. shaded lines. By sternfaces isineant the.

side of thefaces of the teeth which; carry,

the load 'wih'euthe steameris' going astern v andconsequ-entlytheshadediportions of the teeth represent those partswhichreceive the least wear in the normal operation ofthe gear unit. v aI ReferringtoFigure 5 that illustrates an end view of Figure 3 lookingin the direction of the arrow X, and which shows the 'arrangement beforereversal, it will be noted that the inion B is in ei'wa 'ement with themain gear B and that thefirst reduction gear 'B. is in engagement withthe large reduction igear' B Referring now to Fig ure 6, wlnchrepresents the end view of Figured looking in the direction of the arrowY, and which shows the parts after reversal, lt wlll be noted the secondreduction gear A j'is now 1n engagement With main gear B and the firstgear A lsin en-,

gagement with the large gear A It will now be noted that, the shadedportions of the teeth which were the stern sides of the teeth have nowbecome the driving side or forward side of the teeth on the gears,excepting the main gear 'B iwhich is so large that the, wear thereon isvery small, and it need notbe reversed until several pinions -.-havebeen worn out.

It ]S to heunderstood'that where a con- "'nection is required on the endofa shaft which is to be reversed a construction must be provided onboth ends of the shaft in order to permit aconnectionto be made, as rfor example the taper and key way 20 on the ends of the shafts 5 sothatproper consection can be madewith the couplers 4 when the shafts 5 -arereversed. I a

F gure 7 WlllOh illus- Referring now to trates a constructionpermitting'the reversal of the main gears without TQVGI'SlIlg: the mainshaft 16, the gear frame G isprovidedwith seat faces21 and22 which areslightly taand 25 are adaptedto be held by means of" stub screws 26that" are screw threaded into the body 1 27 and-28 on the rings 24 and25.

place.

vpered and onwhi'ch main gear teeth rings 24 C and extend through'theflanges stub screws clamp the gear teeth rings verytightly upon the gearwheel frame so that the gear teeth rings are very rigidlyv held in.Suitable keys one of which is shown" at 30 are adapt-ed to interlockeach of the gear teeth rings and the body so that the These with apropeller shaft; a pair of intermediate shaftsn' each of said shaftsbeing symmetrical about a plane perpendicular to the construction itairline evidentith'at the transmitted, are necessarily helicalfgears.

By tl'iis' arran ement it will appear that tbe lite o'fa gear etism-earlyincreased. I

, 'lhe present in venton" is p rticularl useful in. overcdiningvibration due to. wear in the gearing. The operators of steam turbineparts are very securely unitedlfl By this 3 plants locate difficultiesby sound .and'when r the gears wear so that vibration becomes excessivethe effect on the morale of the operatorsis very depressing becauseitdestroys the elementqon which they depend for safety,'

by finding trouble'before it becomes disas- I trous. Furthermore thisinvention prov des",

for therenewed relation being accomplished by merely reversingsymmetrical interfitted parts, so that the renewal maybe made at,

sea or elsewhere with no special machinery required other thanjthatneededto handle the heavy parts.

lilaving thus described ourinvention, what we claim 18:. v I

1. Driving mechanism for steamships A comprising a large driven gearhaving teeth 1n reversed symmetry about a plane perpendicular to the midpomtof its axisfand constructed to p'ermitready reversal to'change thetrailing faces of the teeth toforward.

faces an intermediate shaft, symmetrical: about ts mid Ipomt;ntermediate gear means mounted; centrally 'onsaid intermediate? shaft,the teeth of I said intermediate gearmeans being in reversed. symmetryabout a plane perpendicular to the midpoint ofthe int-ermediate'shaft topermit the inter-- mediate gear to be reversedby reversing theintermediate shaft in its bearings; a pinion shaft symmetrical about aplane perpendlcular'to its mid point; and aplnion mounted centrally onsaid shaft,-said pinion having its teeth in reversed symmetry about aplane perpendicular to the mid point of theshaft to permit the pinion tobe reversed of all gear elements of the series whereby when teethbecomewornall of the gear elements may be reversed tochange all of thetrailing faces into forward faces.

2.;A power plant for steamships comprising a large gear adapted to beconnected mid point of the shaftyintermediate gear means mountedcentrally on said intermedi ate shafts and operative to transmit power11'5 by ref vet-sing the pinion shaft in itsbearing;said

construction permitting the ready reversal" i to the large gear, each ofsaid intermediate gear means having teeth in reversed symmetry about aplane perpendicular to the mid point of its shaft whereby when theintermediate gear teeth become worn the intermediate shafts may bereadily reversed in their bearings to cause the trailing faces of theintermediate gear teeth to become forward faces; a pair of pinionshafts, each symmetrical about a plane perpendicular to its mid pointand having both ends formed for attachment to the same coupler; a pairof steam turbines, one coupled to each of said pinion shafts, andpinions mounted centrally of the pinion shafts, each of the pinionshaving teeth in reversed symmetry about a plane perpendicular to the midpoint of the pinion shaft whereby when the pinion teeth become Worn, thepinion shafts may be readily uncoupled from the turbines and reversed intheir bearings to cause the trailing faces of the pinion teeth to becomeforward faces.

ANDREW FLETCHER, JR. JAMES A. CAPSTAFF.

